This can also be accomplished via dconf-editor, but that app seems kinda buggy in Fedora 16. When I open dconf-editor from the menu, then go to org>gnome>nautilus>preferences, the keys aren't visible:

I had to click on the windows's min/max button to get the keys to show up:

Then I'm able to select "always-use-location-entry." Here's the resulting view in Nautilus:

Note: These instructions are for Nautilus in GNOME 3. If you're using GNOME 2.30 (in Ubuntu 10.04, for example), you can do the same thing by opening to gconf-editor and navigating to apps > nautilus > preferences and selecting "always_use_location_entry."